Stroke is the leading cause of adult disability in the United States, yet there are very few treatments which have been shown to improve stroke outcome. Obstructive sleep apnea (OSA) affects more than half of stroke patients. Even when adjustment is made for stroke severity, OSA is a predictor of poor recovery after stroke. The physiological effects of OSA may be implicated in impairing the neuronal reorganization which underlies functional recovery after stroke. In addition to these more direct biological effects, the excessive daytime somnolence associated with OSA may impede stroke rehabilitation. Despite the association between OSA and poor stroke outcome, it is unknown whether treatment of OSA after stroke improves stroke recovery. The goal of the proposed project is to assess the feasibility of performing a prospective, randomized, blinded, clinical trial of continuous positive airway pressure (CPAP) versus control (sham) CPAP in stroke patients, and to gain preliminary data on outcome effects.The primary hypotheses to be tested are: (1). Stroke patients with OSA can tolerate active CPAP and control CPAP. (2) Stroke patients during their hospital admission or on the night of discharge from the hospital will be willing to participate in sleep testing and to be randomized into a clinical treatment trial.The secondary aims are to demonstrate that OSA treatment by active CPAP will yield better 90 day outcome in patients with stroke than control CPAP with respect to (1) functional outcome (2) depression (3) quality of life (4) fatigue (5) and sleepiness. Proving the feasibility of the study design would facilitate the planning of a large scale clinical trial of CPAP in stroke patients with OSA. If this large trial shows the benefits of CPAP, a new treatment would become available for more than half of all stroke patients. This would clearly represent a significant medical breakthrough. Evidence-based guidelines for screening and treatment of stroke patients with OSA would then be possible. The candidate is a stroke fellowship-trained neurologist who is dedicated to a career in patient-oriented stroke research. This application proposes a 5-year plan, including formal didactic training in epidemiology and biostatistics, to develop the candidate into an independent stroke researcher. The candidate and mentors are committed to the highest quality clinical research endeavors aimed at reducing the tremendous burden of disease caused by stroke in the United States. The University of Michigan, with a strong Stroke Program, Sleep Disorders Center, and School of Public Health will create the perfect environment for this candidate's career development.